Physiological Responses Of Camellia Oleifera To Different Light Quality During Growth And Development

Camellia oleifera is an important woody oil tree species in the south of our country,which has high economic and ecological value.The country popularized C.oleifera varieties in large areas,so that seedlings in short supply,at the same time the yield per unit area also needs to be improved.Light quality affects all stages of plant growth and development by regulating photosynthetic characteristics,physiological metabolism and morphogenesis.The study on the effect of light quality on the growth and development of C.oleifera can guide seedling raising in production or increase the yield of C.oleifera,it is also helpful to explain the mechanism of light quality affecting the growth and development of C.oleifera.In this study,three-year-old C.oleifera’huashuo’ was used as experimental material,the effects of five light qualities(blue,white,red and blue mix,red and sunlight)on the growth rate,photosynthetic characteristics,microstructure and element content of C.oleifera leaves during leaf development were studied,the effects of flower morphology,hormone content,pollen viability,stigma receptivity,fruit economic traits,kernel microstructure and tea oil quality were studied:1.Effects of light quality on the morphological characteristics,photosynthetic characteristics and element contents of C.oleifera leaves.The growth of new shoots and leaves under red light was significantly lower than that under blue light,red-blue light and sunlight.The photochemical efficiency and electron transfer efficiency under red light were 39.1%and 47.3%lower than those under sunlight,respectively.Blue light inhibited the accumulation of chlorophyll a in leaves of C.oleifera,while red and blue light was beneficial to the increase of total chlorophyll and chlorophyll b contents,and red light decreased the contents of carotenoid.Under blue light,the stomatal area of C.oleifera leaves increased by 23.1%,while under red and blue light,the density of C.oleifera leaves increased by 30%.Under red light,the thickness of palisade tissue decreased by 50.7%,and under red light and red-blue light,the development of sponge tissue was faster than that under blue light and white light.Under blue light,the number of chloroplasts in individual cells was lower than that in sunlight,but the number of lamellar granules and osmiophilic granules were significantly higher than that in sunlight,the phosphorus content was the highest under blue light(5.01 mg/g)and the lowest under sunlight(3.46 mg/g).2.Effects of light quality on the morphological characteristics,fertility and endogenous hormone content of C.oleifera flowers.The number of flowers in white and red light was 21%and 30.3%lower than that in sunlight,respectively.The flower diameter,stigma length and ovary diameter of C.oleifera under red light were significantly smaller than those of other light quality groups,and the pollen viability and stigma receptivity of C.oleifera were the highest under red and blue light,and the pollen tube growth rate was faster,the pollen viability,pollen tube growth rate and stigma receptivity were the lowest under red light.The content of IAA was significantly higher under red light than other light quality groups,while the content of ICA was significantly higher under blue light than other light quality groups The contents of IP,tZ and tZR were the highest in white light group,and were significantly different from those in other light quality groups.The contents of JA,JA-ile and S A were significantly higher in sunlight than those in other light quality groups,but the content of H2-JA was the highest in red-blue light group.The content of ACC in red and blue light was the highest,but it was 11.2%higher than that in sunlight,and the content of ABA in blue and white light was significantly higher than that in other light qualities.Correlation analysis showed that IAA content was negatively correlated with pollen viability and stigma receptivity,while ACC content was positively correlated with pollen viability and stigma receptivity.3.Effects of light quality on the morphological and economic characters of C.oleifera fruit.Under red light,the single fruit weight and fruit diameter of C.oleifera decreased by 16.9%,15.2%and 13.7%,respectively.The seed weight and oil content decreased by 24.2%and 23.3%respectively,the seed weight and oil content decreased by 10.4%and 11.6%respectively under white light.Under blue light,red-blue light and sunlight,the size of fruit,seed weight and oil content of seed kernel were similar,while under red light,the size of kernel cell decreased by 32.9%compared with sunlight,while under red-blue light and blue light,it increased by 17.9%compared with sunlight The average oil body diameter in red and white light keratinocytes decreased by 23.8%and 12.4%compared with that in sunlight,respectively,while there was no significant difference in blue,red and blue light and sunlight,blue light increased the ratio of stearic acid to oleic acid,red light and white light increased the ratio of palmitic acid to linoleic acid,and the composition of red-blue light was similar to that of sunlight.The contents of squalene,sterol and polyphenol in the seeds of C.oleifera under blue light were higher than those in other light quality groups,and the sterol content was 1.1 mg/g,significantly higher than that in sunlight group.The results of correlation analysis showed that the oil content of C.oleifera was closely related to the fruit morphology,economic index and oil body morphology,but the content of secondary metabolites in C.oleifera oil was less related to the fruit morphology and economic index,it has strong correlation with oil body morphology.4.In conclusion,under 200μmolm-2s-1,blue light and red-blue light are beneficial to the growth and development,structure formation and function exercise of the organs of C.oleifera,while white light and red light have inhibitory effects,red Light and blue light were beneficial to the development of fruit organs and the formation of oil,while blue light could promote the accumulation of secondary metabolites,white light and red light inhibited fruit growth,lipid formation and accumulation of secondary metabolites.